Years ago in college at Arizona State University I took a course in mammalogy, the study of mammals. I was biology major, it was an upper level class and turned out to be one of my favorite classes. We learned the characteristics of all mammals including such things as that they are vertebrates, are warm-blooded, have hair or fur somewhere on their bodies, have a single bone in their jaw, have three middle ear bones and feed their young milk. We learned the twenty or so different orders of mammals and their distinguishing characteristics. At the end of the class, I could detail the differences between such mammalian orders such as Lagomorpha (rabbits, hares, pikas), Artiodactyla (even-toed ungulates such as deer and camels) and Cetacea (whales and dolphins). I could tell you how mammary glands were actually modified sebaceous glands, and how the bones in bat’s wings (bats are mammals) were actually thin and elongated finger bones.
For one of the lab portions of the class, we had to go out and actually trap small mammals, then prepare them for scientific display using the proper technique and notation. Armed with a bag of mouse and larger rat traps, I set out into the desert surrounding the school, laying my traps baited with peanut butter under bushes, beneath piles of rocks and in other places I thought rodents might frequent.
I made elaborate maps so I could find my traps again. My first few efforts were unsuccessful. Finally, on my third or fourth attempt, each time setting my traps in different spots, I succeeded in catching a bird in one of my traps. After several weeks of refining my technique, I finally caught several large cotton rats and mice.
The next step was to prepare the specimens appropriately for display. After skinning the animals, being careful to preserve the limbs and tail, the inside of the skin was brushed with talc powder, and the body stuffed with cotton and sewed closed, a stiff wire having been pushed inside the tail to keep it rigid. The skull, which contains many of the characteristics that allow you to distinguish one animal from another, was boiled in a solution until it was bare white bone.
This wasn’t taxidermy. The animals were not displayed in life-like action poses, clutching or clawing at the air, but rather laid horizontally as you might see them if you opened a catalog drawer at the famed Natural History Museum in London or at the Smithsonian. A label was carefully filled out with pertinent details in a precise manner and attached to the left rear leg.
Why am I telling you all this? Well, partly because I hadn’t thought of it for a long time and got a bit carried away, but also because there is one mammal subclass that we learned about, perhaps stranger than all the rest, and that I never imagined I’d see in the wild—until I went to Australia.
Most mammals we are familiar with come under one main subclass: Subclass Eutheria. This subclass includes such mammals as horses, apes, whales, bats, rats, lions and a whole host of other animals we commonly see. But there are two other weirder subclasses of mammals, Metatheria and Protheria. Metatheria are the marsupials, which includes such animals as the kangaroos in Australia and the opossums in the United States. Marsupial mammals are born in an immature state, and most are then carried by the female in pouches.
The remaining subclass, Protheria, are called monotremes of which there are only five living species all of which are found only in Australia and New Guinea.
Monotremes are strange. They are mammals—they have all the mammalian characteristics listed above—but they lay eggs like birds or reptiles. The most well known of the monotremes is the duck-billed platypus, which constitutes one of the five living species of monotremes. The other living species of monotremes are four species of echidna (ih-KID-na), a spiny porcupine-looking animal also known as the spiny anteater.
While we were walking on a coastal trail in Victoria, we saw one, a brown ball of animal about a foot long with prominent spines. It looked like a small porcupine. The echidna was beneath a small shrub with its snout totally buried underground furiously digging around and presumably eating ants.
Echidnas are named after Echidna, a monster from Greek mythology, who was half-woman and half-snake which relates to the animal’s mixed pedigree: part normal mammal and part reptile. One of the first Europeans to describe the echidna was actually Captain Bligh of HMS Bounty fame. After describing the animal and drawing an illustration of it, the animal was roasted and eaten. Its meat was described as having a ‘delicate flavor’.
Echidna mating behavior is a bit bizarre—I’ll leave you to investigate that on your own. The female lays a single egg and deposits it directly into its pouch. Ten days later, a baby echidna called a puggle (initially ‘smaller than a jelly bean’) is born. It laps up milk from milk patches inside the pouch where it stays for several months time.
We watched our echidna for several minutes. The echidna has a relatively slow metabolism and hence, despite the novelty, there was not really much to see. Perhaps the feeling was mutual since after several minutes the echidna turned its back toward us and lumbered off into the bush.